Formula for calculating the distance from the monitor / TV to the eyes?

Question

Monitors

It has long been tormented by the question of how to properly position the monitor and TV. We need a calculation formula, and I think they will be different for a monitor and a TV
1. A monitor for working with a computer. EIZO 27" 2.5K (2560x1440)
2. TV as a home theater in the hall, LG 86" 4K

There are a lot of articles on the Internet, but absolutely different numbers are written everywhere
For the monitor, I currently use this
Windows 10 config 125% scale
Distance to the monitor 80cm

Answer 1

Roughly speaking, the distance to the monitor should be such that you can turn your head to a minimum and the text from the monitor can be read well.

Answer 2

The optimal distance to a 27-inch monitor is arm length + 10-15 cm. I myself have an acer 27 ".

Answer 3

Article on the optimal distance to the TV